<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../vue.js"></script>
</head>

<body>
    <div id="app">
        <button @click="firstName='li'">change</button>
        <h2>全名的{{fullName}}</h2>
        <h2>全名的{{fullName}}</h2>
        <h2>全名的{{fullName}}</h2>
        <h2>全名的{{fullName}}</h2>
        <h2>全名的{{fullName}}</h2>
        <h2>全名的{{fullName}}</h2>
        <h2>全名的{{fullName}}</h2>
        <h2>全名的{{fullName}}</h2>
    </div>
    <script>
        Vue.config.productionTip = false;
        
        const vm = new Vue({
            el: "#app",
            data() {
                return {
                    firstName:"wanhg",
                    lastName:"zhongwang",
                };
            },
            computed:{
                fullName(){
                    console.log("计算");
                    return(
                        this.firstName.toLowerCase() + " " + this.lastName.toLowerCase()
                        
                    )
                }
            }
        })
</script>
</body>

</html>